package com.example.demo.interceptor;

import com.auth0.jwt.exceptions.JWTDecodeException;
import com.example.demo.annotation.PassToken;
import com.example.demo.annotation.UserLoginToken;
import com.example.demo.model.entity.User;
import com.example.demo.service.UserService;
import com.example.demo.utils.TokenUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.lang.reflect.Method;

/**
 * @author KUBUB
 */
public class AuthenticationInterceptor implements HandlerInterceptor {

    @Autowired
    UserService userService;

    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object object) throws Exception {
        // 从 http 请求头中取出 token
        String token = httpServletRequest.getHeader("token");

        // 如果不是映射到方法直接通过
        if (!(object instanceof HandlerMethod)) {
            return true;
        }
        HandlerMethod handlerMethod = (HandlerMethod) object;
        Method method = handlerMethod.getMethod();

        // 检查是否有 PassToken 注解，有则跳过认证
        if (method.isAnnotationPresent(PassToken.class)) {
            PassToken passToken = method.getAnnotation(PassToken.class);
            if (passToken.required()) {
                return true;
            }
        }

        // 检查是否有 UserLoginToken 的注解
        if (method.isAnnotationPresent(UserLoginToken.class)) {
            UserLoginToken userLoginToken = method.getAnnotation(UserLoginToken.class);
            if (userLoginToken.required()) {
                // 执行认证
                if (token == null) {
                    throw new RuntimeException("无token，请重新登录");
                }

                // 获取 token 中的 user id
                String userId;
                try {
                    userId = TokenUtils.getUserID(token);
                } catch (JWTDecodeException e) {
                    throw new RuntimeException("401");
                }
                User user = userService.selectById(Integer.valueOf(userId));
                if (user == null) {
                    throw new RuntimeException("用户不存在，请重新登录");
                }

                // 验证 token
                boolean verifyToken = TokenUtils.verifyToken(token);

                return verifyToken;
            }
            return true;
        }
        return false;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {

    }
}
